Karima El Mahroug, who has been dubbed "Ruby the Heart Stealer" by the Italian press, is alleged to have had sexual relations with Silvio Berluscon in exchange for money and jewelry when she was aged 17.Reuters, file

MILAN, Italy -- Former Italian Prime Minister Silvio Berlusconi was the ringmaster of "bunga bunga" sex parties at his luxurious villa, giving the go-ahead for young women to perform pole dances and stripteases, according to a court document.

Berlusconi, who faces potential expulsion from his Senate seat next week after receiving a final conviction for tax fraud in a separate case, was handed a seven-year jail sentence in June for abuse of office and paying for sex with a minor during the parties.

In a document released on Thursday explaining the reasons behind the conviction, the court said there was sufficient proof that the 77-year-old had sexual relations with former nightclub dancer Karima El Mahroug, who was 17 at the time, in exchange for money and jewelry.

It said Berlusconi directed women to perform and dance erotically during the parties.

"It is proven that the director of the young women's sexual performances was Berlusconi himself," the court said.

Berlusconi has described the evenings as "elegant dinners" and is appealing the verdict. He will not have to serve any jail time for the conviction unless it is upheld after two appeals.

The court said it was Berlusconi who decided when to begin "the so-called 'bunga bunga' in which female guests worked to satisfy the desires of the defendant, that is to 'make him feel bodily pleasures'... performing pole dances, striptease, dressing in disguises and fondling each other."

Evidence also shows Berlusconi was aware that El Mahroug, also known by her stage name "Ruby the Heart Stealer," was under 18 at the time, below the legal age limit for prostitution in Italy, the court found.

In May 2010, the then-prime minister called a Milan police station to instruct officials to release El Mahroug, who was being held on suspicion of stealing a 3,000 euro ($4,000) bracelet.

Berlusconi's lawyers said he had made the call to avoid a diplomatic incident because he believed El Mahroug was the grand-daughter of Hosni Mubarak, then Egypt's president. But prosecutors said he was anxious to cover up their sexual relations.

The court said in the document that if Berlusconi had not known El Mahroug was under-age, he would have had no reason to make the call and try to secure her release.

The prostitution case forms only one part of Berlusconi's legal problems. In August Italy's top appeals court confirmed his conviction for massive tax fraud at his Mediaset TV empire, a decision he says was politically motivated.

The Senate is due to vote on November 27 on whether to expel him from his seat. Berlusconi, whose center-right party is part of Italy's coalition government, has said he may no longer back Prime Minister Enrico Letta if he is kicked out. But a split in his party has left him without the numbers to bring the government down.